A way to only zoom in one direction and to control the length/speed?

[Roemer]

Is there a way to control the zoom behavior, like if I only want to zoom in or zoom out and how fast the zoom should be?
Best for the zoom speed I found so far is the fltSteps by increasing the number of steps and modifying the framerate accordingly.

[bnlcas]

Hey, I just implemented a basic version of this request locally.

In autozoom.py I made a flag for boomerang_clip = True
and changed the end of autozoom.py to reflect this option.

if boomerang_clip:
. frames = [ npyFrame[:, :, ::-1] for npyFrame in npyResult + list(reversed(npyResult))[1:] ]
else:
frames = [ npyFrame[:, :, ::-1] for npyFrame in npyResult ]
moviepy.editor.ImageSequenceClip(sequence = frames, fps=frame_rate).write_videofile(arguments_strOut)

To change the duration, I think the best way to go is to change the number of steps from the default 75 to a duration & frame rate defined by the user:
change
'fltSteps': numpy.linspace(0.0, 1.0, 75).tolist()
to
zoom_steps = int(zoom_duration * frame_rate)
'fltSteps': numpy.linspace(0.0, 1.0, zoom_steps).tolist(),

I would be happy to make a PR to add these changes into this repo. I could also have these features be reflected in the GUI if that helps.

[bnlcas]

This:
https://github.com/bnlcas/3d-ken-burns/blob/add-boomerang-and-duration-controls/autozoom.py

[bnlcas]

@sniklaus - just a follow up. I made a PR for this a few weeks back. Let me know if you would be ok with a merge or if there are any modifications you would like to see before accepting these changes.